Control mechanism



May 1s 1926.,

El. E. THURSTON CONTROL MEGHANISM Filed Nov. l2 1921 2 Sheets-Sheet l $8/528 Affi /BB /325' Hi?" L E. E. THURSTON CONTROL MECHANISM Filed Nov.l2., 1921 2 Sheetsheet 2 Patented May l, 1926..

tisana PATENT esta.

ERNEST B. TURSTON, OF TOLEIDO, OHIO, ASSIGNOR TO THE HA'D'GHTO'NELEVATBJ d6 MACHINE CO., OF TOLEDO, OHIO, A. CORPORATION OF OHIO.

CONTROL MECHANISII.

Application filed November 12, 1921. Serial No. 514,584.

-This invention relates to the control ofv electrically operatedequipment.

This invention has utility when incorporated as an elevator controllerequipped with an alternating electric current drive, having advantages'for smoothness ot' operation at. high speeds, especially' in rangesabove 250l ator for the switch adjacent which said ref-- erencecharacter is placed; and

Fig` 3 shows motor operation curves hereunder.

Inelevator shaft 1 are landings 2 for elevator car 3 in its travel asactuated from hoist line 4. This hoist line 4 extends from the car 3upward about drum 5, and thence about idler 6 to counterweight 7.

Considering the wiring lay-out, power supply lines 8, 9, complete aphase, while lines 10, 11, are the power supply lines completing theother or' second phase of the twophase four-wire alternating` currentsupply. The'various safety devices and their interconnection with thecontroller are herein shown as in the phase supplied by the lines 8. 9.

y The power supply line 9 has branch line 12 extending to emergencyswitch 13 on the car il. located within reach of the operator of thecar, and normally closed. From this emergency switch 13 on the car 3,extends lineH to switch 15, closed when the car carried doors are closedand open when such doors are open, say at a landing. From this doorinterlock switch 15 line '16 extends to switch 17, opened by speedgovernor 18 driven by line 19 from the c ar 3 when the travel of the car3 exceeds the speed or travel rate for which the governor is set. Thedoor interlock switch 15 is shown opened Aby car door 20.

The speed controlled switch 17 has line 22 therefrom to upper overtravelswitch 23, normally closed, and thence by line' 2&1 to lower overtra-velswitch 25, also normally closed. From this switch 25, line 26 extendsthrough landing door interlock switches 27, open if any landing door 28be not closed; thence b v line resistance 30, through slow speed mainswitch coil 31 of slow speed main switch 321` Lcading'from this coil 31is line' 33 to interlock 31 at main high speed switch lVith this switch35 not thrown, the interlock 3l is closed, so that the-line is connectedto line 36 extending to switch -37 as an interlock at down directionswitch 38.. This linterlock 37 has the line 36 thereto also connected byline 39 to interlock 40 at up direction switch 41. are open until thecontroller has operated to determine the direction the elevator car 3 ist0 travel. This means the slow speed main switch 32 has one side of theline to the coil 3l open until the direction 'tor car travel has beendetermined. Furthermore, due to the interlock 34, even though thedirection switch selected be thrown for energizing the coil 3l, suchcoil is deenergized when the main high speed switch 35 closed.

The slow speed main switch 32 has been described as connected into thecontrol system herein disclosed between the power sup ply and interlockson the direction switches 38, 41. f The coil for releasing thaniotonshaft is also connected by interlocksfor operation as a. directionswitch is thrown. To effect this sequence of control, the` line 29 hasbranch 42th interlock fiatthe' down direction switch 3 8, und said.interlock is open as this direction switch 38 is open. Line 44 'from theline `@entends tointerlock 45 at the up'direction switch 41. Thisinterlock 45 is also open when. the up direction switch 41 is open.-'When the up diren- These interlocks 37, 40,

tion switch 41 is closed, the interlock 45.

connects the line Itl,tturougli this interlock with line 46 lextendingbeck to the side of the interlock 43 away from the line 42 thereto.Accordingly with either direction switch 38 or 41 closed, aninterlockconnects` to line 47 vand thence to coil 48 at brake releasing switch49.

From this brake switch coil 48, line 50 extends to central terminal 51engaged by contact 52 of controller 53 inthe car 3. For updirectiontravel of the cai- 3, the controller 53 has its upper end rocked to theleft, shifting the contact 52 first to connect the terminal 51 withterminal 54 of line 55 to upper normally closed limit switch 56, thenc/eby line 57 to the interlock 37 et Vthe down direction switch 38. l/Viththis switch 38 open, the interlock 37 is in position for con nectingtheline 57 with line 58 extendin to' normally closed upper cvertrevelswitc- 1 23, and thence byline 59 past lower over# travel switch25,*a1so normally closedu From this switch 25, the .line 59 is connectedby line 60 tothe mein' power supply line8. The safety devices are all inseries as to the phase of current supply/'trom the lines 8, 9, but suchcircuit is open, due to the inter locks at the direction` switches beingboth o en. -pShiting of the controller 53 to have its Contact 52 engage'terminal 6l permits how of the first energizing circuit from' thesupply line 8 by way of line 62 to energize coil 63 at the up directionswitch 4i. The other side of the coil 63 is connected hy line 64 and theline 42, to the line 29, in communication with the supply line 9. Thecontroller contact 52 is connectalcle for communica-tion with the supplyline 9..

This energizing of the up-direction 'switch coil 63, efects throwing ofthis switch 41, so positioning the interlock 45 that the lines 44, 46,47, energize the coil 48 to throw the brake releasing switch 49. Branchline 65 from the power supply line 8 extends to this switch 49, and asthis switch is closed is connected to line 66 to brake coil 67,

lthence by line 68 completing circuit to the supply line 9.Simultaneously loranchV line 69 from the supply line 11, extending tothe switch 49, is connected to line 70 to brake coil 7l, having line 72therefrom to the power supply line 10. The switch 49 has thus served toenergize both coils 67, 71, oi the brake for operating brake shoes 7 3against the holding action ot' spring 74, to release brake drum onshai't76 so thet motor 77 may be operaed to drive the drum 5 for effectingelevator car travel in up di'- rection. As this lip-direction switch isthrown to closed position, the interlock 40, has connection with theline' 62, 'by wey of the lines 39, 36, the interlock 34 et the niain'high speed switch 35 and 'thence by the line 33, to energize the coil 3lat the switch This slow speed mein switch coil-is ener- .I 4from thenceby heersers gized inasmuch as the line 33 is thus connected to thesupply line 9, while the lino 62 is connected to the supply line 8.

The control o't the power lines as brought about by closing the switch41 for up-direction travel, may now he considered. The power supply line9 has branch 79 to the down direction switch 38, andline 89 thereirom tothe 11p-direction switch 41. This line 80 is connected by the closing ofthis switch 4l to the main slow speed switch 32, by line 81. The power'supply line 8 has branch 82 to" tn'pyup-direction switch 41, connectedh) the closing of this switch 41, to lino 83 extendinglto low speedwinding 84 gud to high speed winding 85 for the' motor 7- l i. vl A Thepower supply lines as controlled by the main slow s eed switch 32connect the resistance ior sow speed starting of the motor 77. The powersupply line 10 has branch 86 to this switch 32, while the other side ofthis phase has connection from the power supply line 1l by ws of line 87directly to the windings 845,8 at the motor 7" As this main slow speedswitch 32 is (i. closed, it connects the line 81' by line 88 throughresistances89, 9U, and line 91 to the slow speed winding 84- .torcompleting the phase therewith as to the line 83. The clos ing of'y thisslow speed switch 82, connects the line 86 to line 92 throughresistances 93, 94, and by way of line to complete the second phase withthe line 87 at the slow speed winding 84 for the motor 77. The

TOO

motor 77 is accordingly fully connected up for starting, and its shaft76 is released to permit such starting for moving the car 3 upward.

The acceleration of the slow speed operation of the motor 77 is broughtabout automatically after the main slow speed switch 32 is closed. Fromthe line 69 at the brake releasing switch 49 extends line 96 to coil 97at 'slow speed accelerating switch 98. and I L way of line 99 to theline 92 at thev` switch 32. The slow speedl accelerating switch 98 isaccordingly thrown immediately the 4switch 32 is thrown. The throwing ofthis switch 98 cuts out resistor comprisingresistcnces 89, 93, as themotor 77 is getting under wai for more rapid building up of the startingof this motor 77. How- 94, islleft in as current modifying means.

The startinol of the motor 77, as herein described has heen by step hystep shitting of the controller 53. In practice, fiore especielly in,passenger' elevator serv..ce, the shifting oi the controller 53 is sorapid that .ict'ually there is not slow speed winding operation forstarting; the .motor 77, hut the starting is on high speed with thenutoniatic acceleration therefor. Accordingly the shifting of thecontroller 53 to have its coneyer, the resistor comprising resistaiiccs90 the terminals 61, 54, while-the motor 77 'is still running above R.I. M., there' may occur an automatic braking or slowing down of themotor 77 independently of an release of the brake shoes` 7 3 forgripping t e drum 75. Asthisis a speed control feature, a governor isconnected up for some of this control operation. As this speed retardingaction is not mechanical in applying the brake shoes 73 for wear, it isa feature of -importancein installationupkeep, even as a safe-guard for.insuring first slowing down of the motor; for yif the controller 53 bethrown into reverse travel selection direction, this slow-down. firstoccurs before power current .is supplied forv` such reverse direction oftravel, thereby avoiding excessive current .consumption at the motor.'This braking occurs by throwing the electric current into the slowspeed windings 81, with the acceleration resistances 89, 93, out, butthe permanent rcsistances or motor slowing down current modifying means90, 94, in. The speed of the motor 7 7 being above that for which theslow speed motor is designed, said latter speed say being 150 R. l. M.,the electric current through the windings 84, brings about a mosteffective retarding generator action, electrically loading the equipmentfor slowing down. The operation is an over speed propulsion of the motorbeyond the synchronous speedof the windings 84. In order that such maynot be too abrupt at the outset and may build up a littlc as acushioning eil'ect, the rcsistances 90,.

94, as permanently in series with the windings 84, may be proportionedto the mass and speed ofthe moving parts. yThis is a factor permittingaccurate adaptation of alternating current electric motors of acommercial design to a wide range of instal- .lations lVith thecontroller 53 oli' the high speed terminal 100, the main high speedswitch 35 opens, andthe interlock 34 falls to have the main slow speedswitch 32 closed'. The torque motor 123 is cle-energized, and the weight138 resets the shaft. 133, opening the switches 142,- 148, 152, andclosing the interlock 104. As the controller 53 has its contact 52 onlyofl' the terminal 100, but still engages the terminal 6l, the brakecoils 67, 71, are still energized, and the beyond synchronous speedbraking action of thewindings 84 is thus far doing all the work ofslowing down. Y

Should the controller be shifted back away from the terminal 61, and offthe terminal 54, the brake coils 6T, 71, are de-energ'izcd, and thebrake switch 49 is opened. The interlock 40 holds the up directionswitch 41 in as long as thc switch 156 is closed. If' this shifting of`the controller 53 occurs before the motor 77 is down to a. speed ofsay200 R. P. M., ,the coils 31 and insiemev (S3-are not l(ie-energized. Thecircuit from the line 9 through the safety devices, in-4 coil 63 by wayof the lines 62, 78, the interlock 40, and the lines 39, 36, to switch156 held closed by governor 157 on the shaft 76 as long as such shaft isrotating at a speed above that selected for the throwing out of thisswitch 156, and herein taken as an eX- auiple as 200 R. l). M. From thisswitch 156, as in an auxiliary control means having a speed responsivedevice actuator therefor, extends line 158 past normally closed downlimit switch 159, thence by line 160 past normally closed upper limitswitch 56, by line 161 to the line 58, connecting through the overtravelswitches with the line 60 to the line 8. f

There is accordingly a holding of the switch in closed position at alltimes when the controller is shifted toward or past elevator carstopping position off 'the' high 'speed terminal, so long as the motorshaft 76 is rotating in excess of the 200 R. P. M. for which the speedresponsive switch 156 is set to open.- So, whether or not the controller53 be only just oii' the high speedterminal, or back to neutral' centralposition, the above synchronous speed braking of the shaft 76 by theslow speed windings 84 automatically occurs, with the permanentresistances 90, 94, in. The switch 156 is accordingly operableindependently of the controller 53. The action of this switch 156 issuch that at all slowing down or stopping operations, the higher travelspeeds are retarded. Inasmuch as the holding action of brake shoes isinversely pro-4 portional to the speed, the greater wear regions incontrol may be handled exclusively by the generator action of the slowspeed windings when the operation is above the synchronous speedthereof, or instead of being exclusive, for the more rapid, but stillsmooth stopping, there may be supplementing of such electrical brakingby mechanical braking action of the shoes 73 upon the drum 75 as forcedby the spring 74. As the speed of the shaft 76 falls below 200 R. P. M.,the switch 156 opens, and the coil 31 is cle-energized, opening theswitch 32, thereby cuttingout the windings 84. The final slowing up ofthe motor 77 is accordin ly handled solely by the brake spring 4. vWhilethe motor 77 is operating in the range of the higher synchronous speedof the windings 85, but with such windings cut out, due to thecontroller position. or the operation i of some stopping device, theaction ofthe switch l@ in holdingthe windings 84 in for generatorbraking action, builds up such braking action as the motor 77slows down,due to the permanent resistances 90, 94.

'For illustrative purposes, reference may .loe had to Fig.. 3 havingspeed ordinates and torquedistance absciss. Curve 163 indicates thetorque-speed curve ot the motor 77 connected up for slow speed startingwith .line voltage on the windings Sfiand no re- ,sistanoe in series,that 1s, without permanent resistances 90, 94:. Curve lG-i is thetorquespeed characteristic ot such slow speed motor operating as agenerator or acting as a brake from the high-Speed operatlon of the'motor down to the slow speed operation.

the windings S4 by the speed control or automatic switch 156 cont-rolledby the governorl 1.137 as long as the shaft 76 is rotating above 200 R.P. M., even though thc controller 53 be shifted to central oti'position.

lt' the controller 53 be shifted only to out out the high speed motorwindings by moving oit the terminals 100 or 129, that is, back to theterminal (5l or to the terminalv 128, the l'n'ake coils 67, 7l, remainenergized and the slow speed motor With its windings 84 in series with.the permanent resistances 90, 94;, acts alone in braking as shown byspeed-dial ance curve 166. The further shifting ot' the controller 53 tothe off position, as the automatic switch. 156 is opened, has the brakespring 74 take hold in ,completing the stopping of the elevator asshownby curve 167.

When the controller 53 is shifted to the full ott' position from full onposition, there not only the generator braking action ot' the slow speedmotor windings 84 as Inodilicd by the resistancesi 94, but such issuppleinentcd by the brake spring 74, and there is automatically electeda smooth, but even more rapid emergency braking or slowing down oi theelevator car as shown by curve 168.

With the holding action ofthe brake shoes by friction inverselyproportional to the 7 speed, the morearduous and wearpromoting vrange istaken by the d namic braking of the .slow speed motor. e harshness ofthe braking action et no iesistmace inthe slow speed windings ismodified by the resistances 90, 94, which, in practice, are proportionedto the kinetic energy of the traveling mass, in order'that the takinghold for stopping may not mean a jerk. The slow speed motor design toincrease the generator load as the shaft 76 slows down from the highspeed, is shown by the cuive 16.3 arching away from vertical speedordinate l 9 as the curve shows speed drop' toward a scissa 170. This isan additional factor in according maximum slowing up action with acushioning at the initial taking hold upon the cutting out ot' 'the highspeed motor. Taking the holding action of the brake by the spring 74 asone at the full speed of the motor 77 ot' 900 it. l). M., then upon thecutting out ot the switch 15G when the motor 77 is 'down to 200 R. l).M., the work given such brake would be as eightly-onc into four, orslightly over one twentieth the work required of the brake at the fullspeed of the motor. Inbrake design, this means `great economy with lesswear and tear in an installation ot superior smoothness of control.

The generator braking by the slow speed motor windings 8i is in the'region above the synchronous speed for such motor, and the tina'lslowing up ot the last stages)'i" stopping, is handled solely by thebrake spring 74. The brake spring 7i may work in conjunction with theslow speed motor windings S-l and the rcsistances 90, Si, at thc higherspeeds, or, as held out by the controller 523, not come in yuntil theautomatic cont-rol Iswitch 156 has acted, or is aboutto act.

lt is to be noted the torque motor for the acceleration switches isconnected' to the power motor for the elevator' and the encrgizingcurrent for the torque motor is through lines at all times directlyconnected with windings o'i' the power motor independently ot' main lineor direction switches therebetween. T his connection of this rotatinglield magnet or torque motor is directly connected to the winding ot'the motor even though there may be resistance between the line currentsupply and the windings of thepower mot-or with the connections to thetorque motor as more remote trom the power motor than said resistance.Therefore it follows, operation oi this torque motor does not dependupon the operation otany switch.

between the power 'motor and rtorque motor`A The torque motor, as hereinshown, is inl operative when supplied with a single phase, and thereforegives a protection against the failure of a switch contact in that itdoes not short 'circuit the resistance in such a failure and thus doesnot allow the power motor winding to be directly across the line` onsingle phase Without resistanceg l VThe invention .disclosed herein, sofar as there may be disclosure of coinn'iiortsub- Y said elevator by lowject mattei with my copending,Y applications for United States LettersPatent, as developing,r into Patents 1,529,675 o'f Mar. 17, 1925, and1,573,207 of Feb., 16, 1926,-each tiled August 23, 1919, isacontinuation thereof.

X'Vhat is claimed and it is desired to secure by Letters Patent is:

1.'The combination with an elevator, a multi-speed alternating currentmotor for operating the elevator, said motor havmg a primary winding, acontroller for the motor, a resistor for the motor in series with saidprimary winding, and means comprising a speed responsive switch formaintaining .a short circuit across a portion only of said resistorabove a predetermined speed of the motor when said controller is shiftedfrom motor 4actuating to motor stopping position.

2. An alternating current electric motor having high speed windings andlow speed primary windings, and a permanent resistor connected at alltimes and only with said low speed primary windings.

3. An elevator, a two speed alternating electric current actuator'including a motor for operating the elevator, said motor having a lowspeed primary winding, a power supply for the motor, a permanentresistor connected at all times and only with the speed primary windingfor the motor, a controller for the motor, and means comprising a speedresponsive switch and con nections thereto from the power supplyloypassing the 'controller for maintaining the low speed windingconnected to the power supply when said switch is closed ,and thecontroller moved from such direction or motor runningl control.

4t. An elevator, a two speed alternating electric current motor foroperating the elevator, said motor having a low speed primary Winding, apower supply for the motor, a permanent resistor connected at all timesand only with the low speed primary winding, a starting resistor :torthe low speed primary winding, a controller for the motor, and meanscomprising a centrifugal speed device connected to be 'driven with saidmotor, a switch operable by said device, and connections thereto fromthe'power supply bypassingy the controller for maintaining the low speedwindingconnccted'to the power supply 'when said switch is closed and thecontroller moved from such direction ot' motor running` control, saidmeans, with. the controller in oil position and the power supply con-'nected to said low speed winding, being o erable to cut off said powersupply from t e low speed primary winding and the permanent resistorbefore the motor stops.

5. Arr elevator/f a--moor therefor` two Speed windings for the motor,

an alternating;l electric current power supply for the motor, anelectromagnetically released brake for the elevator, a controller forcontrolling the connection of the supply to the brake and motor, andmeans for suppleinenting' the retarding action of the brake comprising aspeed responsive switch and connections thereto from the power supplybypassing the controller' for maintaining said current supply to thelesser speed winding when said switch is closed and the con-- trollermoved from such direction of motor running control.

6. Actuating means for an elevator comprising an alternating electriccurrent power supply, anelectric motor provided with windings for onesynchronous speed and windings for a less synchronous speed, a resistorconnected at all times and only with said less synchronous speedWinding, an accelerating resistor for said less synchronous speedwinding, and means for maintaining said current supply to said lesssynchronous speed winding and first resistor above synchronous speed ofsaid less synchronous speed Winding.

7. A motor, an alternating electric power supply therefor, highand lowsynchronous speed windings for the motor, a permanent resistor connectedat all times and only with said low synchronous speed Winding, anaccelerating resistor for said low synchronous speed winding, controlmeans for the motor operable for disconnecting the supply or current tothe motor prior to stopping, auxiliary control meansfor connecting saidlow synchronous speed winding for generator action of the motor instopping, cutting out-said accelerating rcsistor and maintaininop saidsupply 'to said low synchronous spec winding and permanent resistor, anda brake for completingr the stopping oit the motor.

8. An alternating current electric motor having a power winding, a shaftfor the niotor, a brake to: the shaft, means normally setting theybrake, electro-magnetic means for releasing the brake, a. polyphasecurrent power supply *for the motor and electro-magnetic means, means'for mainmotor deceleration, and a manually operable device rendering.control of the brake dependent upon said last mentioned means.

9. An alternatingl current motor having a power winding, a shaft for themotor, a brake for the shaft, means normally setting the brake, analternating electric current power supply for the motor, and meansjforestablishing dynamic braking connections between said motor and supplycomprising current modifying; means for the motoi` thereby supplementingthe brake for stopping the motor.

l0 la a motor central system, a motor, a

115 ,l taining said supply to said winding during resiente '7 high speedwinding for the motor, a second speed winding tor the motor, anaccelerating resistor tor the high Speed winding, an acceleratingTresistor` for the second speed winding, high and second speed switchestor the motor, a controller for the switches and second speed resistor,and a rotating tield magnet connected on the same side ot said highspeed switch as said motor for controllingl the, cutting ont ot saidhigh speed resistor. v

1l. 1n a niotor control system, a motor, high and second speed windingstor the Ainotor, a permanent resistor' .ind .1; starting,r re- 4sisterfor thel second speed winding, a start ing resistor for the hi gh speedwinding, high and second speed switches Y for the motor, a controllershit'tahle from an oli' position to control the switches, and arctatingfield magnet connected on the same side of said high speed switch assaid motor 'for control ling the cutting:r ont'ot said highspcedIrcsistor. i

12. Anelevator, a two speed alternating electric current actuatortherefor including a motor having;l a low speed primary winding. analternating electric current power supply tor the "winding, a brake tor'the inotor. and means for establishing dynamic braking" connectionsbetween the motor and supply comprisingl current niodi tying; means torthe motor thereby supplementing vthe brake lor stopping:r the motor.

1?. ,sin elerater, a two speed alterna l electric current actuatortherefor including a motor having a low speed primarv1 wind ine'` apower snpply for the motor, and means tor establishingr dynamic brakingconncctions between saii'l motor and supply comprising' permanentcurrent :tiow modifying means consisting ot relatively fixed elementsconnected at all times and only with said low speed primar)v windine'.

'1ireversible motor haring' terniinals, alternating electric cin-rentpmrer supply for the motor. accelerating; means for thc motor,acccleratinn` switches 'for said accelting ' eratingr means. rercrsinc.switch means tor the motor, a rotating; nn 'netic field magnetdirectl)vv connected to said motor terminals iinlepcndcnlly ot' saidswitch means tor operating said arceleratiinr sivitches, means inaddition lo sario magnet tor operatingthe reversing: switch means, andacontroller tor operating the magnet in one direction of motor operationand operating the magnet in the opposite direction in the otherdirection ot' motor operation.

15. 'Analternating current electric inotor having; terminals, low andhighspeed windings tor the motor, direction switches for the motor,accelerating means for one o said speed windings of the motor,accelerating switches for said accelerationrneans, a rotating magneticeld magnet directly connected tosaid inotor terminals independently ofsaid switch means tor operating said accel- @rating switches, means inaddition tosaid' magnet tor operating the direction switches, and acontroller for determining operation ot' the magnet in one directionwith one direction switch and in the other direction with the otherdirection switch, said inagnet heine` etiective tor controlling thesaine accelerating means in each of its directions of operation.

lo. il motor having irst and second main switches, direction switches, acontroller' shitahle trom an ott position to control a direction. thetrst main and then the second niain switches, connections Vtor the motorthrough the lirst main switch, starting resistance trom the second mainswitch, a speed controlled switch etective when the vcontroller isshifted from the on position ,fer the second switch for establishingconnections for generatoraction in retarding the motor, a rotatingmagnetic field magnet. tor controlling the cutting out of the starting'resistance, rotating magnetic field mag` not switch means permittingcontroller direct control ot the second inain switch., and

'itch means at the second main switch hypassing the magnet switch meansas the second niain switch is operated, said second nis' 'i switch meanscoacting-to cnt out the tiret lain switch. I lll-ait two speed motor,accelerating resistances tor hotli silieeds ot the motor, a -permarientresistance tor the low speed motor or Yentier, rotating magnetic ieldmagnet, 'for cutting' ont the high Speed resistance, and a controllerfor the speeds ot the motor shiittalilel trom high speed position forgenerator operation ot the vlow speed motor as modified hv saidpermanent resistance in retardingl the. motor.

i8. A. motor haring a low speed connection(y a lirst niain switchtherefor, accelerating; resistance.. a low speed acceleration switchcontrolled for being thrown in automaticallj,7 after the first mainSwitch, a. permanent resistance 'for said low speed motor connection,said motor also having a high speed connection, a second main switchtherefor, accelerating resistance for the high speed motor connection, arotating magnetic field magnet vfor cutting` ont the high speed motoraccelerating resistance, a cont-roller for the motor speeds, and aswitch effective with the controller thrown back trom von position inSnch direction for cnt ting ont the low speed connection. andresistanceas the motor slows down from high speed operation.

'sin alternating current electric motor. and control means tor thestoppingthereof embodying an electromagnetic brake, a resistorinsertahle with the motor for thereby. lessening torque of the motor,and means iD,.-

ico

lao

cluding a controller for braking said motor and at will causing saidelectromagnetic brake to supplement the action of said torque lesseningresistor.

20. An alternating current electric motor` and control means for thestopping thereof embodying an electromagnetic brake, perfor thereby.`lessening torque of the motor,

a controller `for the motor, and aspeed device for holding the motor andpermanent resistance connected during retarding` operation of the motorfor a decrease of the motor operative rate to a determined lspeed.

An elevator, a reversible motor there'- l'or, high and low speedwindings for the motor, an alternating electric current power suppl ffor the motor, a brake for holding the e evator, high and low speedswitches for the respectivewindings, a controller for releasing thebrake and normally operable foi-"connecting directly thehigh speedswitch to the supply in establishing the high speed running condition4for the elevator, and means comprising a speedl responsive switcheli'ective to provide connection for said current supply to the lesserspeed winding and maintainin such connection with the c'ontrollershitted from said running establishing condition to motor reversalposition, there being connectionsfrom the controller for motor reversalrendered ineective until said speed responsive switch is opened.

28. In a-,control system, a motor, a line switch for thelmotoigpolyphase power supply lines for the motor, a controller sliit'tablefrom an oii'., position to control the switch,

a primary winding for the motor connected t0 the switch, a motorstarting resistor, and a rotating magnetic field magnet having polyphaseconnection to said supply lines and on the same side of said switch assaid. motor for controlling the cutting out of said resistor.

24. In a control system, a motor, high and second speed switches for themotor, a controller shiftable from an ofi' position to control theswitches, a second speed primary winding for the motor connected to thesecond speed switch, a motor starting resistor between the motor and.'the high speed switch, a high speed winding for the motor, a powersupply for the motor, a rotating magnetic field magnet connected on thesame side of said switches as said motor for controlling the cutting outof said resistor, and means comprising a speed responsive switch andconnections thereto from the power supply bypassing the controller formaintaining said power Supply to said second speed primary winding abovea predetermined speed of said motor when said switch is closed and thecontroller moved from such direction of motor running control.

In witness whereof I affix my signature.

ERNEST n. THURsToN.

